The art of consultancy

Confidence — I believe it's Epicurus who tells us — is the mean between rashness and cowardice. Consequently it is a prerequisite for those of us who work in the service industries, particularly consultancy.
You should be rash enough to think that even in your short visit to an organisation you can identify endemic issues in the way they work that no one there will have spotted, while wary of stating the bleedin' obvious. You should don your mettle and cast yourself headlong into office politics, careful of treadng on toes. You should be brazen about your subject knowledge, but timorous that any conception you have of best practice could be an appropriate solution.
Above all, be afraid that your client might discover you're a bullshitter and be brave when they do.